EP0649865A1 - Aqueous, self-crosslinking polyurethanevinyl hybrid dispersions - Google Patents

Abstract

Aqueous self-crosslinking binders comprising polyhydrazides and carbonyl-containing urethane-vinyl hybrid polymers and optionally conventional additives.

Description

Coating systems based on aqueous polyurethane dispersions have become increasingly important over the past 15 years due to their good properties such as adhesion to different substrates, abrasion resistance and flexibility and toughness in a further area of application. Polyurethane dispersions are particularly suitable for coating metallic and mineral substrates as well as for plastic and wood painting. Polyurethane resins are generally stabilized in the aqueous phase by means of external emulsifiers or by incorporating sufficient amounts of ionic or nonionic groups into the polyurethane resin. The property profile of polyurethane dispersions can e.g. can be modified by adding vinyl polymer dispersions. The documents US 3,862,074, DE 39 15 459 and EP 0 379 158 selected by way of example describe aqueous coating systems which can be produced by simply mixing a polyurethane dispersion with acrylate dispersions.

Special production processes for vinyl polymers, in which the polymerization of vinyl monomers takes place in the presence of aqueous polyurethane dispersions, are described, for example, in documents EP 0 098 752, EP 0 167 188, EP 0 189 945, EP 0 308 115, EP 0 522 419 and EP 0 522 420. In the case of the patents EP 0 189 945 and EP 0 308 115, the preparation of the mixture of polyurethanes and vinyl polymers proceeds via the stage of a water-dispersible, isocyanate-terminated polyurethane resin which is built up in a solution of vinyl monomers and chain-extended after being converted into the aqueous phase . This is followed by a radical polymerization, in the further Vinyl monomers can be metered. On the other hand, EP 0 167 188 discloses a process which, via the intermediate stage of an isocyanate-terminated polyurethane resin with terminal acryloyl groups, permits the production of polyurethane-acrylate hybrid dispersions. After being diluted with free-radically polymerizable compounds, this unsaturated prepolymer is dispersed in the aqueous phase and chain extended. This is followed by a radical-initiated polymerization in the aqueous phase to give a one-component dispersion with chemically linked polyurethane and acrylate blocks.

Production processes for polyurethane-acrylic hybrid dispersions are also described in EP 0 098 752, EP 0 522 419 and EP 0 522 420. In contrast to the process disclosed in patent EP 0167188, the synthesis of the polyurethane-acrylic hybrid dispersions takes place here via the stage of polyurethane macromonomers with terminal or lateral α, β-olefinically unsaturated groups which have no terminal isocyanate groups and therefore in aqueous form Phase cannot be extended. After these polyurethane macromonomers have been converted into the aqueous phase, a free-radically initiated polymerization is also carried out in the presence of mono- and / or polyfunctional vinyl monomers. None of the above-mentioned polyurethane-vinyl hybrid dispersions or mixtures of polyurethane and vinyl polymer dispersions are self-crosslinking at room temperature or low temperatures.

Vinyl polymers containing carbonyl groups were mentioned in the patent literature more than 20 years ago. They are generally prepared in an emulsion polymerization process by polymerizing vinyl monomers containing carbonyl groups with other vinyl monomers. The patents DE 15 95 393, DE 28 19 092, EP 0 127 834 and EP 0 332 011 are listed as examples. Self-crosslinking aqueous coating systems based on mixtures of polyurethane resins and vinyl polymers are disclosed in EP 0 332 326. Self-crosslinking takes place here via azomethine bonds, which result from a reaction of hydrazine with carbonyl groups. In these coating compositions, at least one polyurethane resin, which has hydrazine or carbonyl groups in the polymer backbone, takes part in the crosslinking. A preferred production variant of the polyurethane polymer is its structure in vinyl monomers, which are polymerized by free radicals after the polyurethane resin has been dispersed in an aqueous medium. This process leads to a polymer mixture consisting of polyurethane resin and vinyl polymer. Mixtures of polyurethane and vinyl polymers which both carry carbonyl groups and can be crosslinked via polyhydrazides are also mentioned in the patent. In the case of a carbonyl functionality, it is introduced into the polyurethane resin during the prepolymer synthesis and / or during the chain extension process. Both options require isocyanate-reactive compounds with carbonyl functionality. The crosslinking of this carbonyl group-containing polyurethane resin can be carried out using polyurethane and vinyl polymers containing hydrazine groups and also polyhydrazides which are not of the polyurethane or vinyl type. Urethane and vinyl polymers exist here as a purely physical mixture. It is known that such systems have a tendency to segregate; in addition to inadequate storage stability, this leads to a deterioration in the mechanical properties, the resistance properties and the film appearance (for example gloss disturbances, film haze).

The task was therefore to create self-crosslinking binders based on urethane and vinyl polymers which have no tendency to separate.

The present invention relates to aqueous, self-crosslinking binders consisting of polyhydrazides and dispersions of carbonyl group-containing polyurethane-vinyl hybrid polymers. These are stable in storage and can crosslink at low temperatures during and / or after film formation via azomethine bonds, which result from the reaction of the hydrazides with the carbonyl groups of the polyurethane-vinyl hybrid polymer. The polyurethane-vinyl hybrid dispersions are obtained by radical-initiated polymerization of ionically and / or nonionically stabilized polyurethane macromonomers which have terminal and / or lateral vinyl groups and optionally terminal hydroxyl, urethane, thiourethane or urea groups, with carbonyl groups and other functional and non-functional vinyl monomers.

The term "carbonyl functionality" is understood to mean the carbonyl group of a ketone or aldehyde compound. The term “hydrazide functionality” is understood to mean the hydrazine, hydrazide or hydrazone group of an organic hydrazine, hydrazide or hydrazone. The binder compositions contain hydrazide and carbonyl groups in a ratio of preferably 1:40 to 2: 1, particularly preferably 1:20 to 2: 1.

The building blocks of the polyurethane-vinyl hybrid dispersions are polyhydroxy compounds A, polyisocyanates B, vinyl monomers C which contain at least one isocyanate-reactive group and at least one vinyl group, hydrophilic monomers D which have at least one nonionic hydrophilic group and / or at least one ionic or ionogenic Contain group, and vinyl monomers E, of which at least one (Ec) has a carbonyl functionality. These polyurethane-vinyl hybrid dispersions are crosslinked by reaction with the polyhydrazides F to form azomethine bonds.

The polyhydroxy compounds A are selected, for example, from the polyhydroxy polyethers A1, the polyhydroxy polyesters A2, the polyhydroxy polyester amides A3, the polyhydroxy polycarbonates A4 and the polyhydroxy polyolefins A5. Optionally, low molecular weight glycols such as glycol itself, di- or triethylene glycol, 1,2-propanediol or -1,3, 1,4-butanediol, 1,6-neopentyl glycol, 1,6-hexanediol, cyclohexanedimethanol, 2,2- Bis- (4'-hydroxycyclohexyl) propane and polyhydric alcohols such as trishydroxyalkylalkanes (e.g. trimethylolpropane) or tetrakishydroxyalkylalkanes (e.g. pentaerythritol) are added. These polyhydroxy compounds can be used both individually and in a mixture.

wobei bedeuten
n,n',n'',n''' = 1 ... 6
m = 10 ... 120
p = 0, 1, 2
Y = H, Alkyl,
die beispielsweise durch Umsetzung von drei- oder mehrwertigen Alkoholen wie Glycerin, Trimethylolpropan und Pentaerythrit mit Epoxiden wie Äthylenoxid und/oder Propylenoxid erhalten werden.The polyhydroxy polyethers A1 can, for example, polyether diols of the formula



H - [-O- (CHR) _n -] _m - OH



be, where R is a hydrogen radical or an alkyl radical with up to 6 carbon atoms, optionally with further substituents, n is an integer from 2 to 6 and m is an integer from 10 to 120. Examples are polyethylene glycols, polypropylene glycols, their Copolymers and polytetramethylene glycols. Polypropylene glycols with a molecular weight of 400 to 5000 g / mol are preferred. Other suitable polyhydroxy polyethers are branched polyhydroxy polyethers of the structure

where mean
n, n ', n'',n''' = 1 ... 6
m = 10 ... 120
p = 0, 1, 2
Y = H, alkyl,
which are obtained for example by reacting trihydric or polyhydric alcohols such as glycerol, trimethylolpropane and pentaerythritol with epoxides such as ethylene oxide and / or propylene oxide.

The polyhydroxy polyesters A2 are produced by esterification of polycarboxylic acids or their anhydrides with organic polyhydroxy compounds. The polycarboxylic acids and the polyhydroxy compounds can be aliphatic, aromatic or mixed aliphatic / aromatic. Suitable polyhydroxy compounds are alkylene glycols such as glycol, 1,2-propanediol and -1,3, 1,4-butanediol, 1,6-neopentyl glycol, 1,6-hexanediol, cyclohexanedimethanol, 2,2-bis- (4'-hydroxycyclohexyl) propane and polyhydric alcohols such as tris-hydroxyalkylalkanes (eg trimethylolpropane) or tetrakishydroxyalkylalkanes (eg pentaerythritol). Suitable polycarboxylic acids having 2 to 18 carbon atoms in the molecule are for example phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, glutaric acid, hexachloroheptanedicarboxylic, tetrachlorophthalic acid, trimellitic acid and pyromellitic acid. Instead of these acids, their anhydrides, if they exist, can also be used. Dimer and trimer fatty acids can also be used as polycarboxylic acids.

entsprechen, in der n bevorzugt 4 bis 6 ist und der Substituent R Wasserstoff, ein Alkylrest, ein Cycloalkylrest oder ein Alkoxyrest ist, wobei kein Substituent mehr als 12 Kohlenstoffatome enthält und die gesamte Anzahl der Kohlenstoffatome des Substituenten in dem Lactonring 12 nicht übersteigt.Other suitable polyhydroxy polyesters are derived from polylactones, for example obtainable by reacting ε-caprolactone with polyols. Such products are described, for example, in US Pat. No. 3,169,945. The polylactone polyols obtained by this reaction are characterized by the presence of a terminal hydroxyl group and by recurring Proportions of polyester derived from the lactone. These recurring molecular parts can be of the formula

in which n is preferably 4 to 6 and the substituent R is hydrogen, an alkyl radical, a cycloalkyl radical or an alkoxy radical, where no substituent contains more than 12 carbon atoms and the total number of carbon atoms of the substituent in the lactone ring does not exceed 12.

in der n und R die bereits angegebene Bedeutung haben.The lactone used as the starting material can be any lactone or any combination of lactones, which lactone should contain at least 6 carbon atoms in the ring, for example 6 to 8 carbon atoms and where there should be at least 2 hydrogen substituents on the carbon atom attached to the Oxygen group of the ring is bound. The lactone used as the starting material can be represented by the following general formula:

in which n and R have the meaning already given.

The lactones preferred in the invention are the ε-caprolactones, in which n has the value 4. The most preferred lactone is the unsubstituted ε-caprolactone, where n is 4 and all R substituents are hydrogen. This lactone is particularly preferred because it is available in large quantities and gives binders with excellent properties.

In addition, various other lactones can be used individually or in combination.

Examples of aliphatic polyols suitable for the reaction with the lactone are ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, dimethylolcyclohexane, trimethylolpropane and pentaerythritol.

The polyhydroxypolyesteramides A3 are derived, for example, from polycarboxylic acids and amino alcohols in a mixture with polyhydroxy compounds. Suitable polycarboxylic acids and polyhydroxy compounds are described under A2, suitable amino alcohols are, for example, ethanolamine and monoisopropanolamine.

entsprechen, worin R' einen Alkylenrest bedeutet. Diese OH-funktionellen Polycarbonate lassen sich durch Umsetzung von Polyolen wie Propandiol-1,3, Butandiol-1,4, Hexandiol-1,6, Diäthylenglykol, Triäthylenglykol, 1,4-Bis hydroxymethylcyclohexan, 2,2-Bis(4'-hydroxycyclohexyl)propan, Neopentylglykol, Trimethylolpropan, Pentaerythrit, mit Dicarbonaten, wie Dimethyl-, Diäthyl- oder Diphenylcarbonat, oder Phosgen herstellen. Gemische solcher Polyole können ebenfalls eingesetzt werden.The polyhydroxy polycarbonates A4 are preferably polycarbonate diols which have the general formula

correspond in which R 'is an alkylene radical. These OH-functional polycarbonates can be obtained by reacting polyols such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, 1,4-bis hydroxymethylcyclohexane, 2,2-bis (4'- Hydroxycyclohexyl) propane, neopentyl glycol, trimethylolpropane, pentaerythritol, with dicarbonates such as dimethyl, diethyl or diphenyl carbonate, or phosgene. Mixtures of such polyols can also be used.

The polyhydroxypolyolefins A5 are derived, for example, from oligomeric and polymeric olefins having at least two terminal hydroxyl groups, α, ω-dihydroxypolybutadiene being preferred.

Other suitable polyhydroxy compounds are polyacetals, polysiloxanes and alkyd resins.

The polyisocyanates B are those commonly used in polyurethane chemistry. Examples of suitable polyisocyanates are trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 1,5-diisocyanato-2-methylpentane, 1,12-diisocyanatododecane, propylene diisocyanate, ethylethylene diisocyanate, 2,3-dimethylethylene diisocyanate, 1-methyltrimethylene diisocyanate, 1-methyltrimethylene diisocyanate, 1-methyltrimethylene diisocyanate , 4-cyclohexylene diisocyanate, 1,2-cyclohexylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-biphenylene diisocyanate, 1,5-naphthylene diisocyanate, 1, 4-naphthylene diisocyanate, 1-isocyanatomethyl-5-isocyanato-1,3,3-trimethylcyclohexane, bis (4-isocyanatocyclohexyl) methane, 2,2-bis (4'-isocyanatocyclohexyl) propane, 4,4'-diisocyanatodiphenyl ether, 2,3-bis (8-isocyanatooctyl) -4-octyl-5-hexylcyclohexene, tetramethylxylylene diisocyanate, isocyanurates of the above diisocyanates and allophanates of the above diisocyanates. Mixtures of such polyisocyanates can also be used.

The monomers C contain at least one vinyl group and at least one group which is reactive toward isocyanate, such as hydroxyl, mercapto and amino groups. Aliphatic hydroxyvinyl compounds having up to 25 carbon atoms are preferred.

Terminal vinyl groups are obtained by the reaction of the isocyanate group-containing macromonomers with vinyl compounds C1 which contain a group which is reactive towards isocyanate groups and also by the reaction of isocyanate group-containing macromonomers with vinyl compounds C2 which contain two or more groups which are reactive towards isocyanate groups if the number of isocyanate groups is less than that of the opposite Isocyanate reactive groups. Lateral vinyl groups are obtained by the reaction of the isocyanate group-containing macromonomers with vinyl compounds C2 which contain two or more groups reactive toward isocyanate groups if the number of isocyanate groups exceeds that of the groups reactive toward isocyanate.

Suitable monovinyl monohydroxy compounds are hydroxyalkyl esters of α, β-unsaturated carboxylic acids such as, for example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate. Other examples are amino group-containing (meth) acrylates, reaction products from monoepoxides and α, β-unsaturated carboxylic acids such as that from versatic acid glycidyl ester and (meth) acrylic acid, reaction products from α, β-unsaturated glycidyl esters or ethers with monocarboxylic acids, for example from glycidyl acid methacrylate and stearate Linseed oil fatty acid. Suitable monovinyl dihydroxy compounds are bis (hydroxyalkyl) vinyl compounds such as glycerol monovinyl ether, monoallyl ether and mono (meth) acrylate or the corresponding compounds derived from trimethylolpropane; further adducts of α, β-unsaturated carboxylic acids, such as (meth) acrylic acid, with diepoxides, e.g. Bisphenol A diglycidyl ether, hexanediol diglycidyl ether; Adducts of dicarboxylic acids, e.g. Adipic acid, terephthalic acid or the like on (meth) acrylic acid glycidyl ester. Also suitable are divinyl dihydroxy compounds and monovinyl trihydroxy compounds which can be prepared, for example, from pentaerythritol by etherifying or esterifying one or two hydroxyl groups with vinyl compounds. These connections lead to branched structures.

The hydrophilic monomers D are polyisocyanates di or polyhydroxy compounds ie which have hydrophilic groups in the molecule. Also other compounds with hydrophilic groups that have several groups that are reactive toward isocyanate, such as polyamino and polymer capto compounds with a hydrophilic group in the molecule belong to the group Dh. Such hydrophilic groups are either non-ionic (s), for example polyalkylene oxide groups such as polyethylene oxide or polypropylene oxide groups or mixed polyethylene oxy-propyleneoxy groups, or they are in ionic form (as a salt) or they are able to form ions in contact with polar solvents such as water. The monomer can carry an anionic or anionogenic group (a), for example a carboxylate, sulfonate or phosphonate group, or a cationic or cationogenic group (k), for example a (substituted) ammonium or amino group.

The monomers of group Di, namely polyisocyanates with hydrophilic groups, are used in the reaction with hydroxy-terminated urethane prepolymers, the monomers in group Dh, namely hydrophilic compounds with one or more groups reactive toward isocyanate, are used in the reaction with isocyanate-terminated urethane prepolymers. Suitable monomers of the Din classification are, for example, reaction products of monohydroxypolyethers such as polyethylene glycol monobutyl ether with at least trifunctional polyisocyanates.

Suitable monomers of the Dhn classification are, for example, reaction products of diisocyanates with groups of different reactivity with a polyalkylene glycol to obtain isocyanate functionality and subsequent reaction of this isocyanate with a dialkanolamine such as diethanolamine. Suitable monomers of the Dha classification are preferably diols which contain an ionic group in the form of the carboxylic acid, phosphonic acid or sulfonic acid group. Examples of this group of monomers are bishydroxycarboxylic acids with 2 to 10 carbon atoms, such as, for example, dihydroxypropionic acid, dimethylolpropionic acid, dihydroxyethylpropionic acid, dimethylolbutyric acid, 2,2-dihydroxysuccinic acid, tartaric acid, dihydroxytartaric acid, dihydroxymaleic acid, dihydroxybenzoic acid 2-hydroxymethylpropanoic acid, 3-hydroxymethyl acid and 1,4-dihydroxybutanesulfonic acid. These monomers are preferably neutralized before the reaction with a tertiary amine such as trimethylamine, triethylamine, dimethylaniline, diethylaniline or triphenylamine in order to avoid a reaction of the acid group with the isocyanate. If the likelihood of such a reaction is low, the acid groups can only be neutralized after they have been incorporated into the polyurethane macromonomer.

Suitable monomers of the Dhk classification are, for example, monoalkyldialkanolamines such as N-methyldiethanolamine or dialkyldialkanolammonium compounds.

The vinyl monomers E are vinyl monomers Ec containing carbonyl groups, alone or in a mixture with other vinyl monomers En, which contain no carbonyl groups.

The vinyl monomers Ec contain vinyl groups and at least one carbonyl group. Examples of such vinyl monomers are methyl vinyl ketone, (meth) acrolein, crotonaldehyde, diacetone (meth) acrylamide, diacetone (meth) acrylate and mixed esters of aliphatic diols with (meth) acrylic acid and acetoacetic acid. The other vinyl monomers En without carbonyl groups which are suitable for the invention are the vinyl monomers which are radically polymerizable in aqueous emulsion, such as vinyl aromatics, for example styrene, vinyl toluenes, vinyl naphthalene; Vinyl esters such as vinyl acetate; Vinyl halides such as vinyl chloride or fluoride; Vinyl ethers, vinyl heterocycles such as N-vinylcarbazole, (meth) acrylonitrile; the esters, imides or amides of unsaturated carboxylic acids such as (meth) acrylic acid, (iso) crotonic acid or vinyl acetic acid with linear or branched alcohols such as methanol, ethanol, propanol, butanol, 2-ethylhexanol or lauryl alcohol. Also suitable are, for example, hydroxyalkyl esters of these carboxylic acids, such as hydroxyethyl or hydroxypropyl (meth) acrylate as well as other vinyl compounds already listed under C, such as glycidyl (meth) acrylate.

The compounds with hydrazide functionality F contain two or more hydrazine, hydrazide or hydrazone groups and preferably have an average molecular weight (M _n ) of <1000. Examples of such compounds are bishydrazides of dicarboxylic acids having 2 to 12 carbon atoms, such as the bishydrazides of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid or the isomeric phthalic acids; Carbonic acid bishydrazide, alkylene or cycloalkylene bis-semicarbazide, N, N'-diaminoguanidine, alkylene bishydrazine such as N, N'-diaminopiperazine, arylene bishydrazine such as phenylene or naphthylene bishydrazine, alkylene bissemicarbazide, bishydrazide from dialonenydenazide. Compounds F with higher functionality are, for example, the hydrazides of nitrilotriacetic acid or ethylenediaminetetraacetic acid.

The polyurethane-vinyl hybrid polymers according to the invention can be produced in various ways.

One way is that a polyaddition product is first prepared by polyaddition of polyhydroxy compounds A and polyisocyanates B. The reaction products AB with isocyanate functionality ABi can then be reacted further with monomers of type C1 to products ABC1. The isocyanate-functional products ABC1i can be reacted further with monomers of the type Dh to give products ABC1Dh. If all of the isocyanate groups have reacted or hydroxyl end groups have now formed, the products can be used without further ado; Isocyanate end groups still present are converted into urethanes, ureas or with alcohols, primary or secondary amines or mercaptans Thiourethanen implemented and only then used. For example, primary amines such as propylamine, butylamine, pentylamine, 2-amino-2-methylpropanol, ethanolamine, propanolamine are suitable for this purpose; secondary amines such as diethanolamine, dibutylamine, diisopropanolamine; primary alcohols such as methanol, ethanol, propanol, butanol, hexanol, dodecanol, stearyl alcohol; secondary alcohols such as isopropanol, isobutanol and the corresponding thio alcohols. These products all have terminal vinyl groups.

The reaction of reaction products ABi with polyfunctional monomers C2 can in turn lead to products with isocyanate end groups ABC2i, in which case all vinyl groups are lateral. The subsequent reaction with the compounds Dh leads to the finished urethane macromonomers, which are further treated as described above with remaining isocyanate functionality, but can otherwise be used directly. In this case, the monomers Dh may also contain only one group that is reactive toward isocyanate. Examples of suitable compounds are aminocarboxylic acids, aminosulphonic acids, aminophosphonic acids, hydroxycarboxylic acids or hydroxysulphonic acids such as aminocaproic acid, aminoacetic acid, aminobutyric acid, aminolauric acid, hydroxybutyric acid, aminomethanesulphonic acid, aminoethanesulphonic acid, aminopropanesulphonic acid, or the hydroxyl aminophosphonic acid, hydroxystonic acid, salicylsulfonic acid, salicylsulfonic acid, salicylsulfonic acid, salicylsulfonic acid, salicylsulfonic acid, salicylsulfonic acid,

The hydroxyl-functional bodies ABC2h with lateral and also terminal vinyl groups are reacted with the isocyanate-functional monomers Di to give the urethane macromonomers; if the isocyanate functionality remains, the procedure is as described above.

A variant is to extend the intermediate product formed from A, B and C in the chain by adding the isocyanate groups of this polyaddition product be reacted with monomers of the Dha type, such as, for example, diamino carboxylic acids or diamino sulfonic acids.

Another preferred reaction route is the reaction of the products ABi first with the monomers Dh to products with isocyanate functionality ABDhi, which can then be reacted with C1 to urethane macromonomers with terminal vinyl groups or with C2 to urethane macromonomers with lateral and little or no terminal vinyl groups .

Reaction products AB with hydroxy functionality ABh are reacted with monomers Di to form isocyanate-functional bodies ABDi, which react with monomers C1 to vinyl-terminal urethane macromonomers. Monomers C2 give urethane macromonomers with lateral vinyl groups and no to a few terminal vinyl groups. The remaining isocyanate functionality is carried out as described above.

The implementations described above can also be carried out in fewer steps, for example two steps or one step, instead of in separate steps.

The urethane macromonomers are prepared by the customary methods known in urethane chemistry. Here, tertiary amines such as triethylamine, dimethylbenzylamine, diazabicyclooctane and dialkyltin (IV) compounds, such as dibutyltin dilaurate, dibutyltin dichloride, dimethyltin dilaurate, can be used as catalysts. The reaction takes place in the melt without solvent, in the presence of a solvent or in the presence of a so-called reactive diluent. Suitable solvents are those which can later be removed by distillation or by dragging with water, for example methyl ethyl ketone, methyl isobutyl ketone, acetone, tetrahydrofuran, toluene, xylene. These solvents can be distilled off in whole or in part after the preparation of the polyurethane macromonomers or after the radical polymerization. In addition, water-dilutable high-boiling solvents, for example N-methylpyrrolidone, can also be used, which then remain in the dispersion. The reactive diluents are vinyl monomers E which are copolymerized in the final stage with the macromonomers containing vinyl groups.

The macromonomers obtained according to the process variants described above are then neutralized if the ionic groups in the monomers which carry such groups have not already been used in neutralized form from the outset.

The acidic compounds are neutralized with aqueous solutions of alkali metal hydroxides or with amines, for example with trimethylamine, triethylamine, dimethylaniline, diethylaniline, triphenylamine, dimethylbenzylamine, dimethylethanolamine, aminomethylpropanol, dimethylisopropanolamine or with ammonia. In addition, the neutralization can also be carried out with mixtures of amines and ammonia. The neutralization of alkaline compounds takes place, for example, with aqueous solutions of mineral acids such as hydrochloric acid or sulfuric acid, or organic acids such as acetic acid.

To produce the polyurethane-vinyl hybrid dispersions according to the invention, the urethane macromonomers obtained according to the preparation variants described above, which contain vinyl groups and may also already contain vinyl monomers E, are converted into an aqueous dispersion by adding water and, after adding (further) Vinyl monomers E, of which at least one (Ec) contains a carbonyl group, are polymerized according to methods known per se by radical-initiated polymerization.

The content of copolymerized vinyl monomers is 1 to 95% by weight, preferably 5 to 70% by weight, based on the weight of the solid of the polyurethane-vinyl hybrid dispersion. The ratio of "soft" and "hard segments" in the urethane macromonomers is 0.30 to 6, particularly preferably 0.8 to 3. For the definition of "soft" or "hard segments", reference is made to developments in polyurethane 1, Chapter 1, page 34, Elsevier Applied Science Publishers, 1984. Suitable initiators for the polymerization are the known free-radical initiators such as ammonium peroxodisulfate, potassium peroxodisulfate, sodium peroxodisulfate, hydrogen peroxide, organic peroxides, such as, for example Cumene hydroperoxide, t-butyl hydroperoxide, di-tert.-butyl peroxide, dioctyl peroxide, tert.-butyl perpivalate, tert.-butyl perisononanoate, tert.-butyl perethyl hexanoate, tert.-butyl perneodecanoate, di-2-ethylhexyl peroxodicarbonate, such as dioverotridicarbonate, such as dioverotridicarbonate, such as dioverotridicarbonate, such as dioverotridicarbonate, such as dioverotridicarbonate, such as dioverotridicarbonate, and also dioverotridicarbonate, such as dioverotridicarbonate, such as dioverotridicarbonate, and also dioverotridicarbonate, such as, for example, dioverotridicarbonate, Azo-bis (isobutyronitrile), azo-bis (4-cyanovaleric acid), or the usual redox systems, e.g. Sodium sulfite, sodium dithionite, ascorbic acid and organic peroxides or hydrogen peroxide. In addition, regulators (mercaptans), emulsifiers, protective colloids and other customary auxiliaries can be added.

If the macromonomers were prepared in a solvent which can be distilled off and which forms an azeotrope with water with a boiling point below 100 ° C., for example in acetone or xylene, this solvent is then distilled off from the dispersion. In all cases, aqueous polyurethane dispersions are obtained. The acid numbers of these polyurethane dispersions are in the range from 5 to 80, particularly preferably in the range from 10 to 40, units.

Preferred embodiments for the preparation of the macromonomers and their polymerization together with the vinyl monomers E to the inventions Polyurethane-vinyl hybrid dispersions according to the invention result from the following process descriptions.

1. Solvent free 1.1 without auxiliary solvents 1.1.1 with terminal OH groups

At temperatures from 100 to 150 ° C, particularly preferably from 120 to 135 ° C, a monomer Dh (for example a polyhydroxy acid), optionally one or more monomers C and optionally low molecular weight polyols in a polyhydroxy compound A with an average molecular weight of 400 to 5000 g / mol dissolved and with a polyisocyanate B or polyisocyanate mixtures (which here and in the following embodiments can also contain the isocyanate-functional vinyl monomers Di) to give an OH-terminated product with an average molecular weight (Mn) of 500 to 12000 g / mol, particularly preferred from 600 to 8000 g / mol. After cooling to a temperature of 30 to 100 ° C, particularly preferably 50 to 70 ° C, a non-isocyanate-reactive vinyl monomer (reactive diluent) E and an at least difunctional, NCO-reactive vinyl compound C2 are added. At this temperature, further addition of polyisocyanate B, which is present in deficit to the OH components, leads to an OH-functional polyurethane macromonomer with an average molecular weight of 700 to 24000 g / mol, particularly preferably of 800 to 16000 g / mol . This resin solution thus obtained is dispersed in water after neutralization with amines or other bases. Further vinyl comonomers Ec and optionally ene are added to the dispersion thus obtained before or during the radical polymerization. In the aqueous dispersion the radical compounds are then used to initiate the vinyl compounds at a temperature of from 0 to 95 ° C., particularly preferably from 40 to 95 ° C. and polymerized when using redox systems at a temperature of 30 to 70 ° C. This creates a solvent-free polyurethane-vinyl hybrid dispersion.

1.1.2 with terminal urethane, thiourethane or urea groups

At temperatures from 100 to 150 ° C, particularly preferably from 120 to 135 ° C, a monomer Dh (for example a polyhydroxy acid) and optionally low molecular weight polyols and optionally one or more monomers C in a polyhydroxy compound A with an average molecular weight of 400 to 5000 g / mol dissolved and reacted with a polyisocyanate B or polyisocyanate mixtures to give an OH-terminated product with an average molecular weight (Mn) of 500 to 12000 g / mol, particularly preferably 600 to 8000 g / mol. After cooling to a temperature of 30 to 100 ° C, particularly preferably 50 to 70 ° C, a non-isocyanate-reactive vinyl monomer (reactive diluent) E and an at least difunctional, NCO-reactive vinyl compound C2 are added. At this temperature, an NCO-terminated resin is built up by further addition of polyisocyanate B and after the further reaction with a monofunctional, isocyanate-reactive compound, selected from alcohols, primary or secondary amines and mercaptans, to give a polyurethane macromonomer with terminal urethane via a , Thiourethane or urea group bonded hydrophilic groups and an average molecular weight of 700 to 24000 g / mol, particularly preferably from 800 to 16000 g / mol. This resin solution thus obtained is dispersed in water after neutralization with amines or other bases. Further vinyl comonomers Ec and optionally ene are added to the dispersion thus obtained before or during the radical polymerization. In the aqueous dispersion, radical initiators are then used at a temperature of 0 to 95 ° C, particularly preferably from 40 to 95 ° C, and polymerized when using redox systems at a temperature of 30 to 70 ° C. This creates a solvent-free polyurethane-vinyl hybrid dispersion.

1.2 with auxiliary solvent 1.2.1 with terminal OH groups

In contrast to process 1.1.1, all components A, C and Dh which are reactive toward isocyanate are dissolved in a solvent which can be fractionated from the aqueous phase or forms an azeotrope with water and directly with a polyisocyanate B or a polyisocyanate mixture to give an OH-terminated polyurethane -Macromonomers with a molecular weight of 500 to 30,000 g / mol, preferably from 700 to 20,000 g / mol. The solvent content is 1 to 80% by weight, particularly preferably between 10 and 50% by weight, based on the solids content of the polyurethane macromonomer. The temperature for this step is between 30 and 100 ° C, particularly preferably between 50 and 80 ° C. After neutralization with amines or other bases, the mixture is dispersed in water. The auxiliary solvent is then distilled from the aqueous phase, possibly under vacuum. The vinyl monomers Ec and optionally En are added to this solvent-free dispersion before or during radical polymerization. Thereafter, free-radical initiators are used to polymerize at a temperature between 0 and 95 ° C., particularly preferably between 40 and 95 ° C., using redox systems at a temperature of 30 to 70 ° C. to give a solvent-free polyurethane-vinyl hybrid dispersion.

1.2.2 with terminal urethane, thiourethane or urea groups

In contrast to process 1.1.2, all components A, C and Dh which are reactive towards isocyanate are dissolved in a solvent which can be fractionated from the aqueous phase or forms an azeotrope with water and directly with a polyisocyanate B or a polyisocyanate mixture to give an NCO-terminated urethane -Macromonomers implemented. The solvent content is 1 to 80% by weight, preferably between 10 and 50% by weight, based on the solids content of the polyurethane macromonomer. The temperature for this step is between 30 and 100 ° C, particularly preferably between 50 and 80 ° C. After the further reaction with a monofunctional, isocyanate-reactive compound, selected from alcohols, primary or secondary amines and mercaptans, to give a polyurethane macromonomer with urethane, thiourethane or urea groups and a molecular weight of 500 to 30,000 g / mol, particularly preferably 700 up to 20,000 g / mol, is neutralized with amines or other bases and dispersed in water. The auxiliary solvent is then distilled from the aqueous phase, possibly under vacuum. The vinyl monomers Ec and optionally En are added to this solvent-free dispersion before or during the radical polymerization. Thereafter, free-radical initiators are used to polymerize at a temperature between 0 and 95 ° C., particularly preferably between 40 and 95 ° C., using redox systems at a temperature of 30 to 70 ° C. to give a solvent-free polyurethane-vinyl hybrid dispersion.

Examples of suitable solvents in the processes corresponding to 1.2.1 and 1.2.2 are acetone, tetrahydrofuran, dioxane, methyl ethyl ketone, methyl isobutyl ketone, toluene or xylene.

2. Contains solvents

When using a non-distillable auxiliary solvent, such as N-methylpyrrolidone, the procedure is exactly the same as in procedures 1.2.1 and 1.2.2, but the distillation is omitted after dispersing. The polymerization is carried out as in methods 1.2.1 and 1.2.2. The solvent content is in the range from 0.1 to 30% by weight, particularly preferably from 1 to 15% by weight, based on the total binder dispersion.

Due to their chemical structure, the polyurethane-vinyl hybrid dispersions according to the invention are suitable for a variety of applications, e.g. for the production of coating systems, as binders for water-thinnable adhesives or as resins for printing inks.

Due to the crosslinking reaction of the self-crosslinking polyurethane dispersions according to the invention which already occurs during film formation at room temperature, these are outstandingly suitable for producing chemical, water and heat-resistant coatings / coatings on thermally sensitive materials, e.g. Wood, paper and plastics.

The polyurethane-vinyl hybrid dispersions according to the invention can be applied to a wide variety of substrates, for example ceramics, composite materials, wood (for example real woods, veneers, chipboard, plywood, etc.), glass, concrete, leather and textiles, in particular plastics, such as polycarbonate, polystyrene, Polyvinyl chloride, polypropylene, polyethylene, PUR-RIM, polyester, poly (meth) acrylates, acrylonitrile-butadiene-styrene polymers and the like, and in particular on metals such as iron, copper, aluminum, (galvanized) steel, brass, bronze, tin , Zinc, titanium, magnesium and the like. They adhere to the various documents without primers or intermediate layers. They can be combined and are generally compatible with other aqueous plastic dispersions and solutions, for example acrylic and / or methacrylic polymers, polyurethanes, polyurea, polyester and epoxy resins, thermoplastics based on polyvinyl acetate, vinyl chloride, vinyl ether, chloroprene, acrylonitrile, acrylonitrile-butadiene-styrene copolymers , etc. They can also be combined with thickening substances based on carboxyl-containing polyacrylates or polyurethanes, hydroxyethyl cellulose, polyvinyl alcohols and inorganic thixotropic agents such as bentonite, sodium-magnesium and sodium-magnesium-fluorine-lithium silicates.

The polyurethane dispersions according to the invention are e.g. Suitable for the production of corrosion-protective coatings and / or intermediate coatings for a wide variety of applications, in particular for the production of metallic and uni-base paints in multi-layer paint structures for the areas of automotive and plastic painting and for the production of primer paints for the area of plastic painting. The binders according to the invention are particularly suitable for the production of basecoats on substrates of all types (as stated above), in particular for the coating of wood and metals. The improved heat resistance combined with the good resistance to condensation is a decisive advantage.

Because of the short flash-off times of the basecoats based on the polyurethane dispersions according to the invention, the pigmented basecoat layer can be overpainted with a clearcoat without a baking step (wet-on-wet method) and then baked together or forced-dried. Basecoats produced with the polyurethane dispersions according to the invention largely provide paint films of the same quality regardless of the stoving or drying temperature, so that they are used both as a refinish for motor vehicles and as a stoving paint for series painting can be used by motor vehicles. In both cases, paint films with good adhesion result on the original paint and with a good resistance to condensation. Furthermore, the brilliance of the varnish layer is not significantly deteriorated after a condensation test.

When formulating water-thinnable lacquers with the polyurethane dispersions according to the invention, the crosslinkers customary in the lacquer industry, such as water-soluble or -emulsifiable melamine or benzoguanamine resins, polyisocyanates, epoxy resins, water-emulsifiable polyisocyanates or water-emulsifiable prepolymers with terminal isocyanate groups, water-soluble or - dispersible polyaziridines and blocked polyisocyanates are added. The aqueous coating systems can contain all known inorganic and / or organic pigments or dyes, as well as auxiliaries, such as e.g. Contain wetting agents, defoamers, leveling agents, waxes, slip additives, stabilizers, catalysts, fillers, plasticizers and solvents.

The coating systems based on the dispersions according to the invention can be applied to all of the application methods known to those skilled in the art to the abovementioned. Apply materials, e.g. by brushing, rolling, pouring, knife coating, dipping and spraying (air, airless, air mix etc.).

The polyurethane-vinyl hybrid dispersions according to the invention can also be used directly for bonding any substrates. To achieve special adhesive properties, the polyurethane-vinyl hybrid dispersions according to the invention can be mixed with other plastic dispersions or solutions (see above). Furthermore, to improve the heat resistance and peel strength, crosslinking agents, such as, for example, water-emulsifiable polyisocyanates or water-emulsifiable prepolymers Terminal isocyanate groups, water-soluble or - emulsifiable melamine or benzoguanamine resins are added.

The adhesives based on the polyurethane-vinyl hybrid dispersions according to the invention can contain the additives customary in adhesive technology, such as plasticizers, solvents, film-binding agents, fillers, synthetic and natural resins. They are particularly suitable for the production of bonds between substrates in the automotive industry, e.g. Bonding of interior components and in the shoe industry, e.g. for gluing the sole of the shoe and the upper. The adhesives based on the polyurethane-vinyl hybrid dispersions according to the invention are produced and processed by the customary methods of adhesive technology used in aqueous dispersion and solution adhesives.

The polyurethane-vinyl hybrid dispersions according to the invention can be used - optionally in a mixture with other binders such as alkyd resins - with the addition of soluble or insoluble dyes or pigments for the production of printing inks.

The invention is explained in more detail by the following examples:

Example 1: (Comparative example: non-self-crosslinking polyurethane-vinyl hybrid dispersion)

232.0 g of a polyester, prepared from 1,6-hexanediol, isophthalic acid and adipic acid, with a hydroxyl number of 88 and an acid number of less than 2 are mixed with 23.0 g of dimethylolpropionic acid, 10.9 g of 1,6-hexanediol and 82 , 8 g of N-methylpyrrolidone-2 heated to 90 ° C. 73.9 g of isophorone diisocyanate are then stirred over a period of 25 to 30 minutes dosed. After a further 60 minutes, 80.0 g of methyl methacrylate and 0.2 g of 2,6-di-tert-butyl-4-methylphenol are rapidly added and homogenized at a temperature of 90 ° C. Then 41.3 g of isophorone diisocyanate are metered in over a period of 10 minutes and stirred at 90 ° C. until the content of free isocyanate groups is 1.11% by weight, based on the total weight. 18.9 g of 2-hydroxyethyl methacrylate are added to the prepolymer solution thus obtained. The reaction is continued until there are no more free isocyanate groups. After adding 53.3 g of methyl methacrylate and 11.4 g of dimethylethanolamine, 758.0 g of water at a temperature of 70 ° C. are added to the prepolymer solution with vigorous stirring. Then 0.7 g of tert-butyl hydroperoxide (80% in di-tert-butyl peroxide) are quickly added dropwise at a temperature of 80 ° C. After a further 30 minutes, a solution of 1.3 g of ascorbic acid and 130.0 g of water is metered in over a period of 90 minutes.

The resulting polyurethane-acrylic hybrid dispersion is cooled to room temperature and filtered through a 5 μm filter cloth. The dispersion has a solids content of 36% and a pH of 7.3.

Example 2:

232.0 g of a polyester, prepared from 1,6-hexanediol, isophthalic acid and adipic acid, with a hydroxyl number of 88 and an acid number of less than 2 are mixed with 23.0 g of dimethylolpropionic acid, 10.9 g of 1,6-hexanediol and 82 , 8 g of N-methylpyrrolidone-2 heated to 90 ° C. 73.9 g of isophorone diisocyanate are then metered in over a period of 25 to 30 minutes with stirring. After a further 60 minutes, 80.0 g of methyl methacrylate and 0.2 g of 2,6-di-tert-butyl-4-methylphenol are rapidly added and homogenized at a temperature of 90 ° C. Then 41.3 g of isophorone diisocyanate are metered in over a period of 10 minutes and stirred at 90 ° C. until the free isocyanate group content is 1.11% by weight, based on the total weight. 18.9 g of 2-hydroxyethyl methacrylate are added to the prepolymer solution thus obtained. The reaction is continued until there are no more free isocyanate groups. After adding 37.3 g of methyl methacrylate, 16.0 g of diacetone acrylamide and 11.4 g of dimethylethanolamine, 658.0 g of water at a temperature of 70 ° C. are added to the prepolymer solution with vigorous stirring. Then 0.7 g of tert-butyl hydroperoxide (80% in di-tert-butyl peroxide) are quickly added dropwise at a temperature of 80 ° C. After a further 30 minutes, a solution of 1.3 g of ascorbic acid and 130.0 g of water is metered in over a period of 90 minutes.

The resulting polyurethane-acrylic hybrid dispersion is cooled to room temperature and filtered through a 5 μm filter cloth. 8.2 g of adipic dihydrazide, dissolved in 100 g of water, are then added with stirring. The dispersion has a solids content of 36% and a pH of 7.5.

Example 3: (Comparative example: non-self-crosslinking polyurethane-vinyl hybrid dispersion)

232.0 g of a polyester, prepared from neopentyl glycol, 1,6-hexanediol, isophthalic acid and adipic acid, with a hydroxyl number of 41 and an acid number of less than 2, together with 23.0 g of dimethylolpropionic acid and 2.4 g of 1,4-butanediol dissolved in 175.8 g of methyl ethyl ketone under reflux. 93.3 g of 4,4'-dicyclohexylmethane diisocyanate are then metered in with stirring over a period of 30 to 35 minutes and stirred at the reflux temperature until the free isocyanate group content is 1.16% by weight, based on the total weight . In the so obtained Prepolymer solution are added 0.2 g of 2,6-di-tert-butyl-4-methylphenol and 49.3 g of a reaction product of glycidyl versatate with methacrylic acid. The reaction is continued at the reflux temperature until there are no free isocyanate groups. After adding 13.0 g of triethylamine, 1000.2 g of water at a temperature of 60 ° C. are added to the prepolymer solution with vigorous stirring. The solvent methyl ethyl ketone is then azeotropically separated from the dispersion obtained by vacuum distillation. After the addition of 107.7 g of methyl methacrylate, 107.7 g of 2-ethylhexyl acrylate and 0.7 g of tert-butyl hydroperoxide (80% in di-tert-butyl peroxide), the temperature is raised to 80 ° C. After a further 30 minutes, 1.3 g of ascorbic acid, dissolved in 130 g of water, are metered in over a period of 90 minutes.

The resulting polyurethane-acrylic hybrid dispersion is cooled to room temperature and filtered through a 5 μm filter cloth. The dispersion has a solids content of 35% and a pH of 7.4.

Example 4:

232.0 g of a polyester, prepared from neopentyl glycol, 1,6-hexanediol, isophthalic acid and adipic acid, with a hydroxyl number of 41 and an acid number of less than 2, together with 23.0 g of dimethylolpropionic acid and 2.4 g of butanediol-1, 4 dissolved in 175.8 g of methyl ethyl ketone under reflux. 93.3 g of 4,4'-dicyclohexylmethane diisocyanate are then metered in with stirring over a period of 30 to 35 minutes and stirred at the reflux temperature until the free isocyanate group content is 1.16% by weight, based on the total weight . 0.2 g of 2,6-di-tert-butyl-4-methylphenol and 49.3 g of a reaction product of glycidyl versatate with methacrylic acid are added to the prepolymer solution thus obtained given. The reaction is continued at the reflux temperature until there are no free isocyanate groups. After adding 13.0 g of triethylamine, 900.2 g of water at a temperature of 60 ° C. are added to the prepolymer solution with vigorous stirring. The solvent methyl ethyl ketone is then azeotropically separated from the dispersion obtained by vacuum distillation. After adding 92.3 g of methyl methacrylate, 92.3 g of 2-ethylhexyl acrylate, 30.8 g of diacetone acrylamide and 0.7 g of tert-butyl hydroperoxide (80% in di-tert-butyl peroxide), the temperature is brought to 80.degree elevated. After a further 30 minutes, 1.3 g of ascorbic acid, dissolved in 130 g of water, are metered in over a period of 90 minutes.

The resulting polyurethane-acrylic hybrid dispersion is cooled to room temperature and filtered through a 5 μm filter cloth. 15.8 g of adipic dihydrazide, dissolved in 100 g of water, are then added. The dispersion has a solids content of 34% and a pH of 7.6.

Example 5: (Comparative example: non-self-crosslinking polyurethane-vinyl hybrid dispersion)

285.6 g of a polyester, prepared from 1,6-hexanediol, isophthalic acid and adipic acid, with a hydroxyl number of 80 and an acid number less than 2, together with 22.1 g of dimethylolpropionic acid, 2.5 g of 1,4-butanediol, 10.5 g glycerol methacrylate and 0.2 g 2,6-di-tert-butyl-4-methylphenol dissolved in 120 g acetone under reflux. Subsequently, 99.3 g of 4,4'-dicyclohexylmethane diisocyanate are metered in with stirring over a period of 30 to 40 minutes and stirred at the reflux temperature until no free isocyanate groups are present. After adding 12.5 g of triethylamine, 1092.2 g of water at a temperature of 60 ° C. are added to the prepolymer solution with vigorous stirring. The solvent is acetone then separated from the dispersion obtained by vacuum distillation. After adding 90.0 g of methyl methacrylate, 90.0 g of n-butyl acrylate and 0.7 g of tert-butyl hydroperoxide (80% in di-tert-butyl peroxide), the temperature is raised to 80.degree. After a further 30 minutes, a solution of 1.3 g of ascorbic acid and 130 g of water is metered in over a period of 60 minutes.

The resulting polyurethane-acrylic hybrid dispersion is cooled to room temperature and filtered through a 5 μm filter cloth. The dispersion has a solids content of 34% and a pH of 7.2.

Example 6:

285.6 g of a polyester, prepared from 1,6-hexanediol, isophthalic acid and adipic acid, with a hydroxyl number of 80 and an acid number less than 2, together with 22.1 g of dimethylolpropionic acid, 2.5 g of 1,4-butanediol, 10.5 g glycerol methacrylate and 0.2 g 2,6-di-tert-butyl-4-methylphenol dissolved in 120 g acetone under reflux. Subsequently, 99.3 g of 4,4'-dicyclohexylmethane diisocyanate are metered in with stirring over a period of 30 to 40 minutes and stirred at the reflux temperature until no free isocyanate groups are present. After adding 12.5 g of triethylamine, 992.2 g of water at a temperature of 60 ° C. are added to the prepolymer solution with vigorous stirring. The solvent acetone is then separated from the dispersion obtained by vacuum distillation. After adding 75.0 g of methyl methacrylate, 75.0 g of n-butyl acrylate, 30.0 g of diacetone acrylamide and 0.7 g of tert-butyl hydroperoxide (80% in di-tert-butyl peroxide), the temperature is raised to 80 ° C increased. After a further 30 minutes, a solution of 1.3 g of ascorbic acid and 130.0 g of water is metered in over a period of 60 minutes.

The resulting polyurethane-acrylic hybrid dispersion is cooled to room temperature and filtered through a 5 μm filter cloth. Then 15.4 g of adipic dihydrazide, dissolved in 100.0 g of water, are added. The dispersion has a solids content of 34% and a pH of 7.4.

The novel, self-crosslinking polyurethane-acrylic hybrid dispersions are characterized by improved resistance to water, solvents and chemicals.

A comparative test of non-crosslinking and self-crosslinking coating systems based on the polyurethane-acrylic hybrid dispersions Examples 1-6 was carried out in accordance with the furniture standard DIN 68861, part 1B. Before the application to mahogany veneered wooden panels, the wetting agent Byk 346 (manufacturer: Byk Chemie GmbH) and the coalescing agent butyl diglycol (= BDG) were added. A wet film with a layer thickness of 150 μm was applied twice to the test plates from the paints thus produced. After a drying phase of 10 days at room temperature, the resistance to the substances listed in the table below was determined.

Example 7:

232.0 g of a polyester, prepared from 1,6-hexanediol, isophthalic acid and adipic acid, with a hydroxyl number of 88 and an acid number of less than 2 are mixed with 23.0 g of dimethylolpropionic acid, 10.9 g of 1,6-hexanediol and 82 , 8 g of N-methylpyrrolidone-2 heated to 90 ° C. 83.2 g of diphenylmethane-4,4'-diisocyanate are then metered in over a period of 25 to 30 minutes with stirring. After another 60 minutes, be at a temperature from 90 ° C 80 g of methyl methacrylate and 0.2 g of 2,6-di-tert-butyl-4-methylphenol quickly added and homogenized. 46.5 g of diphenylmethane-4,4'-diisocyanate are then metered in over a period of 10 minutes and stirred at 90 ° C. until the free isocyanate group content is 1.11% by weight, based on the total weight . 18.9 g of 2-hydroxyethyl methacrylate are added to the prepolymer solution thus obtained. The reaction is continued until there are no more free isocyanate groups. After the addition of 37.3 g of methyl methacrylate, 16.0 g of diacetone acrylamide and 11.4 g of dimethylethanolamine, 672.5 g of water at a temperature of 70 ° C. are added to the prepolymer solution with vigorous stirring. Then 0.7 g of tert-butyl hydroperoxide (80% in di-tert-butyl peroxide) are quickly added dropwise at a temperature of 80 ° C. After a further 30 minutes, a solution of 1.3 g of ascorbic acid and 130.0 g of water is metered in over a period of 90 minutes.

The resulting polyurethane-acrylic hybrid dispersion is cooled to room temperature and filtered through a 5 μm filter cloth. 8.2 g of adipic dihydrazide, dissolved in 100 g of water, are then added with stirring. The dispersion has a solids content of 37% and a pH of 7.7.

Example 8:

232.0 g of a polyester, prepared from 1,6-hexanediol, isophthalic acid and adipic acid, with a hydroxyl number of 88 and an acid number of less than 2 are mixed with 23.0 g of dimethylolpropionic acid, 10.9 g of 1,6-hexanediol and 82 , 8 g of N-methylpyrrolidone-2 heated to 90 ° C. 57.9 g of tolylene diisocyanate (mixture of isomers: 20% 2,6-isomer, 80% 2,4-isomer) are then metered in over a period of 25 to 30 minutes with stirring. After a further 60 minutes at a temperature of 90 ° C 80 g of methyl methacrylate and 0.2 g of 2,6-di-tert-butyl-4-methylphenol were quickly added and homogenized. Then 32.4 g of tolylene diisocyanate (mixture of isomers: 20% 2,6-isomer, 80% 2,4-isomer) are metered in over a period of 10 minutes and stirred at 90 ° C. until the content of free isocyanate groups 1, 11% by weight based on the total weight. 18.9 g of 2-hydroxyethyl methacrylate are added to the prepolymer solution thus obtained. The reaction is continued until there are no more free isocyanate groups. After the addition of 37.3 g of methyl methacrylate, 16.0 g of diacetone acrylamide and 11.4 g of dimethylethanolamine, 672.5 g of water at a temperature of 70 ° C. are added to the prepolymer solution with vigorous stirring. Then 0.7 g of tert-butyl hydroperoxide (80% in di-tert-butyl peroxide) are quickly added dropwise at a temperature of 80 ° C. After a further 30 minutes, a solution of 1.3 g of ascorbic acid and 130.0 g of water is metered in over a period of 90 minutes.

The resulting polyurethane-acrylic hybrid dispersion is cooled to room temperature and filtered through a 5 μm filter cloth. 8.2 g of adipic dihydrazide, dissolved in 100 g of water, are then added with stirring. The dispersion has a solids content of 36% and a pH of 7.2.

Example 9:

232.0 g of a polyester, prepared from neopentyl glycol, 1,6-hexanediol, isophthalic acid and adipic acid, with a hydroxyl number of 41 and an acid number of less than 2 are mixed with 23.0 g of dimethylolpropionic acid, 2.4 g of 1,4-butanediol dissolved in 175.8 g of methyl ethyl ketone under reflux. Then, over a period of 30 to 35 minutes, 89.1 g of diphenylmethane-4,4'-diisocyanate are metered in with stirring and stirred under reflux until the free isocyanate group content is 1.16% by weight, based on the total weight. 0.2 g of 2,6-di-tert-butyl-4-methylphenol and 49.3 g of the reaction product of glycidyl versatate with methacrylic acid are added to the prepolymer solution thus obtained. The reaction is continued under reflux temperature until there are no free isocyanate groups. After adding 13.0 g of triethylamine, 969.0 g of water at a temperature of 60 ° C. are added to the prepolymer solution with vigorous stirring. The solvent methyl ethyl ketone is then azeotropically separated from the dispersion obtained by vacuum distillation. After adding 92.3 g of methyl methacrylate, 92.3 g of 2-ethylhexyl acrylate, 30.8 g of diacetone acrylamide and 0.7 g of tert-butyl hydroperoxide (80% in di-tert-butyl peroxide), the temperature is raised to 80 ° C increases. After a further 30 minutes, a solution of 1.3 g of ascorbic acid and 130.0 g of water is metered in over a period of 90 minutes.

The resulting polyurethane-acrylic hybrid dispersion is cooled to room temperature and filtered through a 5 μm filter cloth. Then 15.8 g of adipic acid dihydrazide, dissolved in 100 g of water, are added with stirring. The dispersion has a solids content of 38% and a pH of 7.5.

Example 10:

232.0 g of a polyester, prepared from neopentyl glycol, 1,6-hexanediol, isophthalic acid and adipic acid, with a hydroxyl number of 41 and an acid number of less than 2 are mixed with 23.0 g of dimethylolpropionic acid, 2.4 g of 1,4-butanediol dissolved in 175.8 g of methyl ethyl ketone under reflux. Subsequently, over a period of 30 to 35 minutes, 62.0 g of tolylene diisocyanate (isomer mixture: 20% 2,6-isomer, 80% 2,4-isomer) are metered in with stirring and stirred under reflux until the content of free isocyanate groups 1.16% by weight based on the total weight, is. 0.2 g of 2,6-di-tert-butyl-4-methylphenol and 49.3 g of the reaction product of glycidyl versatate with methacrylic acid are added to the prepolymer solution thus obtained. The reaction is continued under reflux temperature until there are no free isocyanate groups. After adding 13.0 g of triethylamine, 942.0 g of water at a temperature of 60 ° C. are added to the prepolymer solution with vigorous stirring. The solvent methyl ethyl ketone is then azeotropically separated from the dispersion obtained by vacuum distillation. After adding 92.3 g of methyl methacrylate, 92.3 g of 2-ethylhexyl acrylate, 30.8 g of diacetone acrylamide and 0.7 g of tert-butyl hydroperoxide (80% in di-tert-butyl peroxide), the temperature is raised to 80 ° C increases. After a further 30 minutes, a solution of 1.3 g of ascorbic acid and 130.0 g of water is metered in over a period of 90 minutes.

The resulting polyurethane-acrylic hybrid dispersion is cooled to room temperature and filtered through a 5 μm filter cloth. Then 15.8 g of adipic acid dihydrazide, dissolved in 100 g of water, are added with stirring. The dispersion has a solids content of 37% and a pH of 7.0.

Claims (13)

Aqueous self-crosslinking binders, consisting of polyhydrazides and carbonyl group-containing urethane-vinyl hybrid polymers and, if appropriate, customary additives. Aqueous self-crosslinking binders according to Claim 1, characterized in that the polyhydrazides have an average molecular weight (M _n ) of <1000 and are aliphatic or aromatic or mixed aliphatic / aromatic compounds having at least two hydrazine, hydrazide and / or hydrazone groups. Aqueous self-crosslinking binders according to claim 1, characterized in that the carbonyl group-containing urethane-vinyl hybrid polymers are obtainable by free radical polymerization of vinyl group-containing urethane macromonomers together with other vinyl monomers, at least one of the vinyl monomers containing one or more carbonyl groups, and the mass content of vinyl blocks in the polyurethane-vinyl hybrid dispersion, based on the mass of the solid, is between 1 and 95%, preferably between 5 and 70%. Aqueous self-crosslinking binders according to Claims 1 and 3, characterized in that the carbonyl group-containing urethane-vinyl hybrid polymers can be obtained together with other vinyl monomers by radical-initiated polymerization of vinyl group-containing urethane macromonomers, at least one of the vinyl monomers containing one or more carbonyl groups, and the vinyl groups are chemically bonded to the chain ends of the urethane macromonomers (terminal) and / or along the macromonomer chain (lateral). Aqueous self-crosslinking binders according to Claims 1 to 4, characterized in that the polyhydroxy compounds used to prepare the urethane macromonomers are selected from the polyhydroxy polyethers, the polyhydroxy polyesters and the polyhydroxy polycarbonates. Aqueous self-crosslinking binders according to Claims 1 to 4, characterized in that the hydrophilic compounds used to prepare the urethane macromonomers are selected from isocyanate-functional or hydroxy-functional polyalkylene oxides and hydroxy-functional anionic, anionogenic, cationic or cationogenic compounds. Aqueous self-crosslinking binders according to Claims 1 to 4, characterized in that the vinyl monomers without a carbonyl group are selected from the group of the esters of aliphatic alcohols with 1 to 12 C atoms and of unsaturated carboxylic acids from the group (meth) acrylic acid, (iso) crotonic acid and vinyl acetic acid, from the group of the vinyl esters, the vinyl ethers, the vinyl aromatics such as styrene, vinyl toluenes or vinyl naphthalenes, and the vinyl monomers with at least one carbonyl group are selected from the group of the aliphatic unsaturated mono- or dialdehydes or the aliphatic unsaturated ketones. Aqueous self-crosslinking binders according to Claims 1 to 4 and 7, characterized in that the vinyl monomers without carbonyl groups are esters of aliphatic alcohols with 1 to 12 C atoms and (meth) acrylic acid. Aqueous self-crosslinking binders according to Claims 1 to 8, characterized in that the ratio of the number of hydrazine to carbonyl groups 1:40 to 2: 1, preferably 1:20 to 2: 1. Use of binders according to Claims 1 to 9 in printing ink resins, adhesives and coating agents for wood, paper, plastics, leather, textiles and metallic substrates, optionally in combination with crosslinking agents, other resins, and other additives such as pigments, leveling agents etc. Use of binders according to Claims 1 to 9 in basecoats for the coating of metals. Use of binders according to Claims 1 to 9 in basecoats for the coating of wood. Use of binders according to claim 12 in basecoats for the coating of plastics.